On Mon, 21 Nov 2005 19:49:11 -0600, Scott Lewis<slewis@...
>At 03:22 PM 11/21/2005, charliesbirdblog@... stated:
>>I took this part-albino Cactus Wren this morning (21 Nov 2005) at
>>Papago Park, just outside Phoenix. Note "colourless" softparts, but dark eye.
>A question for the biologists on the list. Is there such a thing as a
>partial albino? I was under the impression that a critter was either
>albino or not. And, that a mutation like this probably has some other name.
It depends on the biologist. There is unfortunately no longer a standard
definition for the term "albino." Your restrictive use of the term "albino"
apparently is quite recent and apparently originates with Paul Buckley.
I think there is a lot of confusion over the terms albinism and leucism
the terms have been used to mean various things by various authorities.
Some widely accepted definitions from the Cornell Laboratory of Ornithology
In the 1985 edition of "A Dictionary of Birds" edited by Campbell
and Lack. An entry by C.J.O. Harrison lists the following types of
Abnormal Pigmentation, Atypical pigmentation, Schizochroism, Pigment
replacement, Gynandromorphs, Pigment deficiency, Pattern variations,
and Feather structure abnormalities.
The following appears in the discussion under "Atypical pigmentation:"
"Partial loss of pigment, affecting all the colours present and
reducing them in intensity, is rare. It is called 'dilution' by bird
breeders and 'leucism
' in scientific writings, although the latter
term is also used at times for various forms of schizochroic loss (see
below) of single pigments which make the plumage appear paler...."
So defined, the phenomenon of true
(dilution of all pigments)
is much rarer than schizochroism (involving a loss or dilution of only
some pigments), so "leucistic" should probably be used rarely, and not
merely as a jargon replacement for the more popular vernacular
"partial albino." In most cases where you hear the pedantic, "There's
no such thing as 'partial albino' the correct term is 'leucistic'",
the authority may be misusing the term.
For more information see a history of uses of the terms "albinism" and
" collected by Floyd Hayes at:
If the purpose of language is to communicate, let's use words which
are reasonably unambiguous and understandable to the widest possible
Joseph Morlan, Pacifica, CA 94044 jmorlan (at) ccsf.edu
Birding Classes start Feb 7 in SF
California Bird Records Committee http://www.wfo-cbrc.org/cbrc/